The Pinyin Input Tool is an extension for Firefox. After installing it, a blue 拼 (pin) button will on the right side of the status bar at the bottom of your browser. You can use it to convert pinyin text with numbers into pinyin text with tone marks. Just type in some pinyin with numbers in to any plain text field on any browser page, highlight it and click the button.

It uses the same conversion algorithm as the online pinyin tone tool I wrote three and a half years ago. The advantage of this Firefox plugin is convenience. It’s very fast and you can use it on any plain text form on any page, including email services.